The present invention relates to a manufacturing method of magnetic resin compound, and more particularly to a manufacturing method of magnetic resin compound capable of regenerating magnetic resin compound, green material and others out of the standard occurring in the manufacturing stage a of neodymium-iron-boron system quenched resin magnet.
Prior arts relating to a compound of rare earth magnet powder and resin include Japanese Laid-open Patent No. 59-136907. This prior art presents:
1. A manufacturing method of samarium-cobalt system magnet using a thermoplastic resin by injection molding method, in which by using R2TM17 (where R is a rare earth element such as samarium and TM is a transition metal, or mainly cobalt) as samarium-cobalt system magnet powder, as compared with the case of using RCo5, the injection-molded magnet, or the compound of rare earth magnet powder such as sprue or runner and resin composition can be more easily ground to be presented again for injection molding.
2. It is easier to handle by demagnetizing the injection-molded magnet or sprue or runner of the molded piece.
3. When the material regenerated from the injection-molded magnet or the sprue or runner of the molded piece is mixed with a kneaded material, there is suppressed lowering of magnetic performance or mechanical properties. It is hence an object thereof to manufacture the samarium-cobalt system resin magnet efficiently in an industrial scale by injection molding.
It is, however, known well that the samarium-cobalt system magnet powder is inferior in resource balance because samarium and cobalt are much contained.
In the case of the magnet being manufactured by injection molding, the sprue and runner occupy 80 to 90% of the entire molded piece of the magnet in a small magnet weighing not more than several grams, such as the one used in the driving source of peripheral device for multimedia PC (personal computer) or the like, and the materials such as samarium-cobalt system magnet powder and thermoplastic resin are spent wastefully in the non-usable parts such as sprue and runner rather than the magnet main body, and energy and materials for injection molding are consumed, which is not preferable from the viewpoint of saving energy and saving resources. Moreover, for injecting the kneaded plastic fused strands to fill in the molding die cavity, the mixing rate of the samarium-cobalt system magnet powder must be 65 vol. % or less. However, keeping the mixing rate of the magnet powder at 65% or less is not advantageous from the standpoint of seeking the magnetic performance for making the best of the magnetic potential of the rare earth magnet.
To increase the volume percentage of the samarium-cobalt system magnet powder and make the best of the magnetic potential of the rare earth magnet powder, it is advantageous to compress the rare earth magnet powder strongly together with thermal polymerizing resin such as epoxy resin because the sprue and runner are not required and the magnetic performance is enhanced.
In the prior art, however, nothing has been known about a technique for compressing the rare earth magnet powder including samarium-cobalt system magnet powder strongly in a specified magnet shape together with thermal polymerizing resin such as epoxy resin.
On the other hand, because there is at present mass use of rare earth resin magnet in the driving source of peripheral device of multimedia PC or the like, it is desired to save resources by using neodymium-iron-boron system quenched magnet powder having an alloy composition excellent in resource balance as compared with the samarium-cobalt system magnet powder, and reduce the disposal amount of magnet materials by reusing the magnetic resin compound of rare earth magnet powder and thermal polymerizing resin.
The invention therefore relates to the neodymium-iron-boron system quenched resin magnet excellent in resource balance of alloy composition as compared with the samarium-cobalt system magnet powder, and used in quantities in the driving source of peripheral device of multimedia PC or the like, and more particularly to a manufacturing method of green matter formed by strongly compressing neodymium-iron-boron system quenched magnet powder resin compound, and a manufacturing method for reusing the magnetic resin compound composed of neodymium-iron-boron system quenched magnet powder and thermal polymerizing resin, so that the disposal amount of the precious magnet material can be reduced.
The invention provides a manufacturing method of magnetic resin compound comprising step 1 of mixing magnet powder and an organic solvent solution of a thermal polymerizing resin in wet process, and step 2 of solvent removal-pulverizing-sorting into adequate particle size range, in which fine powder out of adequate particle size range discharged at step 2 is granulated within the adequate particle size range after the wet process mixing of step 1 and solvent removal-pulverizing-sorting of step 2, so that the disposal amount of magnet material may be reduced.